The long-term objectives of this project are to understand the role and mechanism of action of N-cadherin in the invasive process related to bladder carcinomas. Preliminary work has identified decreased invasive potential associated with the down regulation of N-cadherin in bladder carcinoma cells. We hypothesize that N-cadherin is a positive mediation in this model. To identify the molecular domain(s) of N-cadherin responsible for eliciting the invasive phenotype we will create chimeras between E- and N-cadherinn genes assaying for in vitro invasive capacity in appropriate transfected cells. We propose that the juxtamembrane domain (JMD) of N-cadherin is critical in generating the invasive behavior and this will be tested directly using a construct where the JMD of N-cadherin is deleted. The P120 protein is associated with the JMD of cadherins and is likely an important regulator of cadherin function. Distinct p120 isoforms have been identified in bladder carcinoma cells expressing different cadherins where p120-1A is the predominant isoform found in invasive, N-cadherin expressing bladder cells. To investigate the importance of this association for invasion, we will isolate clones of p120 isoforms and introduce p120-1A into bladder cell lines expressing E- or E-/N-cadherin lacking p1201A. We further propose to identify the signaling pathway(s) linked to N-cadherin and invasion, initially evaluating established signaling events implicated in this process. Since the goals of this proposal focus upon the role of N-cadherin in invasion of bladder carcinoma cells, we propose to develop new in vitro models representing different states of the metastatic process in which we can investigate the role(s) of N-cadherin. Validation of N-cadherin in bladder tumor metastasis would identify it as a potential marker of invasion and a possible therapeutic target for the future.